This project will assess the impact of the Government of Kenya's Cash Transfer for Orphan and Vulnerable Children Program (CT-OVC) on the prevention of HIV. The study has 3 main aims. The first is to continue a unique social experiment initially designed to evaluate the impact of the program on a range of poverty, health and education outcomes among the target group of ultra-poor households with OVC. We will field a 4 year follow-up survey on the same households, approximately 13000 individuals and 6000 OVC, one-third of who were randomized out of the program the remainder who began receiving a cash grant in 2007. The second aim is to assess the impact of the program on HIV risk among adolescents, which will be accomplished by expanding the original survey instrument to include new modules on sexual activity and risky behavior among adolescents. The third aim will assess whether the program has affected time preferences for adults, and how time preferences, subjective risk assessment and risk aversion influence the propensity to engage in choice behavior with long time horizons such as savings, human capital investment and risky sexual activity. PUBLIC HEALTH RELEVANCE: Two-thirds of the estimated 33m people infected with HIV live in sub-Saharan Africa (SSA). Young people (age 15-24) account for nearly half of all new infections in SSA and HIV prevalence is 2 and sometimes 4-5 times higher among young women relative to men. This project examines the impact of the Kenya Cash Transfer for Orphans and Vulnerable Children program on adolescent sexual activity and HIV risk. It is the first study to assess the HIV prevention impact of a large scale government cash transfer program. The rigorous experimental design involving over 2200 households will provide new, robust estimates of the potential for cash transfer programs to reduce HIV transmission among young people in SSA.